Symmetric pseudo-random code phase modulation all-optical focusing coherent lidar method and device

Abstract

The invention discloses a method and device for a symmetrical pseudo-random code phase modulation all-optical focusing coherent laser radar. The output beam of a laser light source is divided into a signal beam and a local oscillator beam by a polarization-maintaining beam splitter; the signal beam is aligned by a symmetrical pseudo-random code. Perform high-speed electro-optic phase modulation, then transmit to the target and receive the echo beam of the target, and receive the echo beam and the local oscillator beam to obtain a coherent receiving signal; the first amplitude type linear array spatial light modulator is used to load the coherent receiving signal Delayed symmetric pseudo-random code; at the same time, the original symmetric pseudo-random code is passed through a variable delay circuit to obtain a variable-delay symmetric pseudo-random code, and all-optical focusing is performed on the variable-delay symmetric pseudo-random code and the delayed symmetric pseudo-random code Processing, the high-precision distance information of the long-distance target is obtained through the time delay of the focus point. The invention can realize high repetition frequency lidar distance detection, and has the characteristics of miniaturization of the whole system and easy operation.

Description

technical field [0001] The invention relates to the technical field of laser radar, in particular to a method and device for a symmetrical pseudo-random code phase modulation all-optical focusing coherent laser radar. Background technique [0002] The use of lidar to measure the target distance in a complex environment, with high real-time performance and measurement accuracy, is an urgent need for autonomous driving environment perception. ability is important. At present, the main principles of laser radar are single pulse time-of-flight method and continuous wave signal frequency modulation technology. The advantages of single-pulse time-of-flight ranging are simple structure and mature technology. The disadvantage is that when working at a long distance, the laser needs to have a very high peak power. In order to ensure the safe operation of the laser, the repetition frequency of the outgoing pulse is low. , so it is difficult to improve the spatial resolution of the m...

AI Technical Summary

Problems solved by technology

The advantages of single-pulse time-of-flight ranging are simple structure and mature technology. The disadvantage is that when working at a long distance, the laser needs to have a very high peak power. In order to ensure the safe operation of the laser, the repetition frequency of the outgoing pulse is low. , so the spatial resolution of the measurement is difficult to improve

The traditional correlation processing method is all digital, because the distance resolution of the coded waveform is proportional to the modulation rate, that is, the higher the modulation rate, the higher the range resolution, and the higher the modulation rate, the greater the amount of calculation. Therefore, it takes a long time to image the target, and the requirements for the operating environment are also high. Usually, the high-performance Field Programmable Logic Array (FPGA) is the core, and the electronic system is complex and expensive. one of the main bottlenecks

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